1. Field of the Invention
The present invention relates to electronic devices with printed matter containing servo control information located such that it can be sensed and used to perform servo control.
2. Description of the Related Art
Electronic devices such as image scanners, facsimile machines and copy machines use an image sensor, i.e., Charge Coupled Device (CCD), Contact Image Sensor (CIS), or Bucket Brigade Device (BBD), to read images. A carriage on which an image sensor is mounted is driven by a motor that is servo-controlled by a servo controller. A variety of conventional techniques have been employed for the servo control.
However, in the past, a rotary encoder with a linked gear attached to a motor shaft and a photo interrupter that detects rotations of the rotary encoder have been used to control the speed of the carriage. Also, a position sensor to detect an initial position (home position) of the carriage is separately provided to control the initial position of the carriage. The additional parts, including separate sensor and associated parts, increases the complexity of the devices, makes it more time-consuming to assemble at factory, and poses an obstacle to lowering the cost of such electronic devices.